Species Profile: Red-bellied newt

Hello again, welcome back to animals under threat. Today, we will be covering a species of newt that spends most of its life on life. Say hello to the red-bellied newt (Taricha rivularis).

The Red-bellied newt is one of four highly poisonous newt species that belong to the Genus Taricha. Unlike the other three species of newt, the red-bellied newt is characterized by the lack of yellow in their eyes, red belly and grainy red/brown skin on top (Amphibian Specialist Group, 2014). This species of newt is native to the United States and is found in Southern Humboldt County, Sonoma County, Mendocino County and California (Reilly et al, 2014). Red-bellied newts have an amazing homing ability that allows them to find their way back to the same stream which they were currently living in (Kuchta and Tan, 2006).

Red-bellied newt by unknown

 

 

 

Like most newt species, the Red-bellied newt produces a neurotoxin tetrodotoxin to repel predators. The newt will lift its front limbs and stand on its lower limbs and tail to reveal its red abdomen while closing its eyes. This threating position works to scarce off most predators, but the Common Gartersnake (Thamnophis sirtalis) has a high resistance to the toxin and continues to feed on red-bellied newts (Edmund et al, 2002). Newts also have the ability to regenerate body parts if they are damaged.

Common Gartersnake by Wilson and male newt by Zachary Lim.

 

 

Even though this species of newt lives on land, they require water to lay their eggs. The newt will migrate to find clear rivers/streams and transform into their aquatic phase and find females to mate with. Many eggs are placed under rocks/roots and hatch into baby larvae, although this depends on the temperature as some hatch faster in higher temperature. The larvae stage lasts around 4-6 months where they leave the stream and live in underground shelter until they reach breeding age 4-6 years (Packer, 1963).

 

Baby newt larvae by Gary Nafis and eggs by Jessica Miller.

 

The biggest threat to this species of newt is low genetic diversity and inbreeding. Most populations of this newt is spread out and has low genetic variation between them. They travel to new streams to breed, but there is little genetic exchange between the groups as females would most likely mate with males that can protect their streams (Kuchta and Tan, 2006).

 

Next time, we will be covering an unusual mammal that looks like a reptile and can curl into a ball for defense.

 

 

 

References

Edmund D. Brodie Jr, Ridenhour, B.J. & E. D. Brodie III 2002, "THE EVOLUTIONARY RESPONSE OF PREDATORS TO DANGEROUS PREY: HOTSPOTS AND COLDSPOTS IN THE GEOGRAPHIC MOSAIC OF COEVOLUTION BETWEEN GARTER SNAKES AND NEWTS", Evolution, vol. 56, no. 10, pp. 2067-2082.

 

Kuchta, S.R. & Tan, A. 2006, "Limited Genetic Variation Across the Range Of The Red-bellied Newt, Taricha Rivularis", Journal of Herpetology, vol. 40, no. 4, pp. 561-565.

 

IUCN SSC Amphibian Specialist Group 2014. Taricha rivularis. The IUCN Red List of Threatened Species 2014: e.T59470A56239017.

 

Packer, W.C. 1963, "Observations on the Breeding Migration of Taricha rivularis", Copeia, vol. 1963, no. 2, pp. 378-382.

 

Reilly, S.B., Portik, D.M., Koo, M.S. & Wake, D.B. 2014, "Discovery of a New, Disjunct Population of a Narrowly Distributed Salamander (Taricha rivularis) in California Presents Conservation Challenges", Journal of Herpetology, vol. 48, no. 3, pp. 371-379.

 

Picture references

https://en.wikipedia.org/wiki/Common_garter_snake

https://en.wikipedia.org/wiki/Red-bellied_newt

http://www.californiaherps.com/salamanders/pages/t.rivularis.html